I spent some time yesterday making impulse files of one of my reel-to-reel decks and I want to share them here. I think they turned out well and capture the character of it. The machine is a Tascam 22-2, a stereo 1/4" reel-to-reel that records in "full track" format at 7.5 and 15ips. The tapes I used were vintage Scotch 150, Scotch 203 and Maxell 35-90B. I recorded tones at 0dB and "HOT" with the needle slamming to get saturation. That level was different depending on the tape. I also recorded at the two different speeds, which gives a very obvious change in frequency response.
Find them here: http://audio.entropyandchaos.com/impulses/tascam22-2/
They I've tested them with Acoustic Mirror, Samplitude Room Simulator, and Convology XT. They should work with a variety of different convolution processors, but I can't guarantee. You're free to use and share them as you wish, though of course, you may not sell them.
Let me know if you give them a try!